I have noticed the same thing- just the top octave for me. I've looked at it on a guitar tuner and it does drift out by quite a few cents. Generally I can usually correct it using the fine tune, sometimes I leave it because it can sound kind of cool. I would also be interested to know if there's a fix using a trim pot.
I'm already on my second Minibrute. The first one I got had a glitchy pitch bend wheel, which produced random pitches just above the centre. I tried updating the firmware, nothing happened, so I took it back.
Sorry for going slightly off topic, but the tuning thing did make me think, have I had two dodgy units in a row, or is the tuning a result of the VCO design?